The present invention generally relates to control devices, such as a mouse, a trackball, and a keyboard. Control devices typically have one or more keys that a user can manually depress to activate specific functions of a computer program.
The user's finger typically applies a downward activation force on a key of the control device to activate the key. However, the user may desire a different actuation force for the key to increase her comfortable use of the control device. That is, some users may benefit from keys with a lower actuation force (or lower stiffness) while other users may prefer keys having a larger actuation force (or higher stiffness). Additionally, a user may prefer to adjust the activating force for one key to be different from the activating force for another key on the same control device.
A user may have other individual preferences for the actuation of the keys of a control device. For example, a user may desire a different key travel or time for a key to activate. Some users may prefer relatively short key travel and fast activation for relatively fast response of the control device, whereas other user may prefer longer key travel and relatively slower activation of the control device. Control devices having keys that have relatively long keystroke travel may prevent unintended actuation of keys when inadvertently tapped or bumped.
Mechanisms that permit a user to adjust the actuation force of the keyboards keys are described in U.S. Pat. No. 5,879,088 and U.S. Pat. No. 5,220,318. U.S. Pat. No. 6,952,528 describes a mechanism that allows a user to adjust the force to activate the shutter release button of a camera. U.S. Pat. No. 4,899,631 describes a mechanism that allows a user to adjust the force to activate the keys of electronic musical instruments, such as electronic pianos.
Some control devices with scrolling elements have included force-dependent inputs. For example, U.S. Pat. No. 6,198,473 and U.S. Pat. No. 6,879,316 describe input devices with force-dependent keys that allow the speed of scrolling to be controlled dependent on the force applied to the keys. However, the above control devices focus on variations in functions enabled by adjustments in pressure on the key during the operation of a control device.
Accordingly, new devices are needed that permit users to adjust the key's preset, initial stiffness, or the actuation force required to activate the key.